In recent years, mobile electronic devices have become widely used such as a mobile phone and a camera including an LED lighting device with an LED element applied thereto (refer to patent literature 1 for example).
Hereinafter, a description is made of a configuration of a conventional LED lighting device described in patent literature 1 using FIG. 5. FIG. 5 is a sectional view of the conventional LED lighting device.
As shown in FIG. 5, LED lighting device 11 is composed of circuit substrate 12 with an electrode pattern formed thereon; packaging body 13 mounted on circuit substrate 12, including reflecting surface 13A; LED element 14 as a light-emitting element fixed to packaging body 13; and lens body 15 provided on packaging body 13.
LED lighting device 11 has lens body 15 disposed facing the upper side (close to an irradiation target) of LED element 14. This structure reflects light emitted from LED element 14 on reflecting surface 13A of packaging body 13 and collects light reflected and emitted upward with lens body 15. Consequently, LED lighting device 11 is obtained with a favorable amount of light radiation.
With conventional LED lighting device 11, however, lens body 15 as a light-emitting surface is disposed so as to face the upper side of LED element 14 to ensure appropriate light distribution. Accordingly, the thickness of LED lighting device 11 itself increases, which is unfavorable when incorporating the lighting device into a mobile electronic device which requires downsizing and slimming down.
Hence, in order to solve the above-described problem (i.e. the thickness of LED lighting device 11), a light guide body used for such as a lighting device for a liquid crystal display device of sidelight type may be used for light distribution. However, a light guide body is usually used for emitting light onto the liquid crystal display panel directly above the light guide body from the side surface of the panel, and does not support light distribution when photographing with a mobile electronic device such as a mobile phone and a camera.
For this reason, an LED lighting device is desired that can decrease its thickness while ensuring favorable light distribution.